A display device comprises, for example, an array substrate, a counter-substrate facing the array substrate, an electro-optical layer provided between the array substrate and the counter-substrate, and an external circuit substrate mounted on the array substrate. As the bases of the array substrate and the counter-substrate, glass substrates are commonly used. However, in a display device comprising a curved display area, resinous substrates having flexibility are employed for the bases.
When the external circuit substrate is mounted on the array substrate, the terminal portion of the array substrate is exposed by trimming the counter-substrate. When the base of the counter-substrate is a glass substrate, the counter-substrate can be easily trimmed by making a cut and bending the counter-substrate. When the base of the counter-substrate is a resinous substrate having flexibility, the counter-substrate cannot be broken along the cut by merely bending the counter-substrate. To trim the flexible counter-substrate, it is necessary to irradiate it with laser light or cut it with rotary teeth.
Since the electro-optical layer such as a liquid crystal layer or an organic electroluminescent layer is thin, the distance between the counter-substrate and the array substrate is short. When the counter-substrate is trimmed with laser light, the array substrate may be damaged as well as the counter-substrate. Thus, a technology for forming a metal layer reflecting laser light on the array substrate to protect the array substrate is suggested.
However, lines for transmitting a video signal, etc., are densely packed in the terminal portion of the array substrate exposed by trimming. When a metal layer is formed on the lines, coupling is generated between the lines and the metal layer. The apparent resistance of the lines is increased. When the resistance of the lines is increased, the S/N ratio of the signal transmitted to the lines is decreased. Further, the number of manufacturing steps is increased to form the metal layer. In general, since the adhesive force of the sealing material used to attach the array substrate and the counter-substrate is strong. Thus, the edge portion of the cut counter-substrate cannot be easily removed from the adhesive. Various other problems are present regarding the trimming of the counter-substrate.